Are Omega-3 fatty acids healthy?

Author: Attabey Rodríguez-Benítez

Editors: Jimmy Brancho, Andrew McAllister, and Noah Steinfeld

When I got sick as a child, my great-grandmother used to treat me with unpleasant fish oil. She would say, “bébete esto para que te pongas mejor y tengas un corazón fuerte” (“drink this so you can get better and have a strong heart”). Both of my parents also swore by fish oil, taking these enormous yellow pills, which I did not take myself because I was afraid to choke on them. These large fish oil pills were full of omega-3 fatty acids. My family explained that the supplements helped with high blood pressure, but never explained why they worked. As it turns out, there is still quite a lot of debate in the scientific community as to how omega-3s impact human health.

What are omega-3 fatty acids?

In fatty acids, omega (ω) refers to the methyl end of the molecule (on the right in Figure 1) as opposed the carboxylic acid end (-COOH, on the left in Figure 1), which is known as the alpha end. The number “3” refers to the placement of the first carbon with a double bond from the omega end i.e. If it is the third carbon then it is Omega-3, if it is the sixth then it is Omega-6. Though there are many types of fatty acids in our bodies, Omega-3s are the most studied and are most often attributed health benefits. In our bodies, there are 3 major omega-3 fatty acids (Figure 1). α-linoleic acid (ALA) is not produced by our bodies and thus is considered an essential fatty acid, meaning that it must be supplied in our diet. Nuts and grains such as soybeans and walnuts are chock full of ALA. After ingestion, ALA is metabolized to eicosapentaenoic acid (EPA) by inserting two carbons and one double bond (Figure 1 yellow circle). EPA can then be converted to docosahexaenoic acid DHA also by introducing two carbons and a double bound (Figure 1 yellow circle). Unlike ALA, EPA and DHA are not essential fatty acids since our bodies can generate them. EPA and DHA are, however, supplemented in our diet from sources like fish.

Throughout the years, several studies have found that consumption of omega-3 fatty acids helps reduce coronary heart disease (CHD) death among patients with prior CHD and these fatty acids also confer a benefit for those who have suffered heart failure. However, there is not enough evidence to determine whether omega-3s have a health benefit for people without prior CHD. This effect is mainly attributed to EPA and DHA, though the exact mechanism by which these compounds protect us from diseases is unclear. Nonetheless, fatty acids seem to affect multiple processes in our bodies that keep us healthy, especially in the heart.

In 2012, fish oil/omega-3 pills were the most popular supplement in the US. 7.8% of the population takes some sort of fish oil supplement. Nonetheless, some scientists are concerned that these supplements are unsafe. Fatty acids are highly susceptible to breaking down into less healthy molecules such as lipid peroxides. This breakdown reaction is initiated by reactive oxygen species where a reactive molecule will steal one electron from a fatty acid. Losing this electron makes fatty acids extremely reactive, allowing them to further react with molecular oxygen to form lipid peroxides (Figure 2). The effects of lipid peroxides have not yet been studied in-depth in humans, but some lipid peroxides have been shown to react with DNA, potentially causing mutations and even cancer. One study measured top-selling omega-3 supplements, finding levels of peroxides and other related products that exceeded international industry standards. Perhaps these supplements could be improved if the Federal Drug Administration (FDA) were to regulate them. By removing these harmful byproducts, health benefits of fish oils could be enhanced.

Attabey completed her bachelor’s degree at the University of Puerto Rico, Río Piedras. Currently, she is a doctoral student in the program of Chemical Biology at the University of Michigan. After her first year she joined the labs of Prof. Alison R.H Narayan and Prof. Janet L. Smith. She focuses on using enzymes as chemical tools for the synthesis of natural products and elucidating their mechanisms of action through structural biology. In addition to research and contributing to MiSciWriters Attabey has a Spanish science blog, En Arroz y Habichuelas, where she writes about science for the general public and in Spanish! She also enjoys reading comics (Saga, Paper Girls, Bitch Planet, etc.), watching movies with a scoring above 7 on IMDB, and eating disgusting amounts of popcorn! You can follow her on Twitter and connect on LinkedIn.